Specific and differential inhibition of very-long-chain fatty acid elongases from Arabidopsis thaliana by different herbicides.
Specific and differential inhibition of very-long-chain fatty acid elongases from Arabidopsis thaliana by different herbicides.
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DOI：
10.1073/pnas.0404600101
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发表时间：
2004-08
影响因子：
11.1
通讯作者：
S. Trenkamp;W. Martin;K. Tietjen
中科院分区：
文献类型：
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作者：
S. Trenkamp;W. Martin;K. Tietjen
在高等植物中，极长链脂肪酸（VLCFA）是疏水聚合物的主要成分，其防止叶表面干燥并为花粉粒提供稳定性。在拟南芥VLCFA延伸酶（VLCFAE）的21个编码基因中，有17个在酿酒酵母中异源表达。六VLCFAE，包括三个已知的延长酶（FAE 1，KCS 1和KCS 2）和三个以前未知的基因产物（编码At 5g 43760，At 1g 04220和At 1g 25450）被发现是酶活性与内源性酵母脂肪酸底物，并在一定程度上与外部提供的不饱和底物。通过气相色谱/质谱法测定在表达酵母菌株中积累的VLCFA的谱。在测试的延伸酶中发现了关于其延伸产物的显著特异性，所述延伸产物包括长度为20-30个碳原子的饱和和单不饱和脂肪酸。活性VLCFAE揭示了对氧乙酰胺、氯乙酰苯胺和其他测试化合物的高度不同的敏感性模式，而酵母内源性VLCFA产生（涉及其在鞘脂合成中的不相关延伸酶（ELO））不受影响。几种化合物抑制一种以上的VLCFAE，有些抑制所有六种活性酶。这些发现将VLCFAE确定为广泛使用的K（3）类除草剂的靶标，这些除草剂已经在商业上使用了50年，为为什么对这类除草剂的自发抗性是罕见的提供了重要线索，并指出了拟南芥VLCFAE家族成员之间底物特异性和产物谱的复杂模式。
In higher plants, very-long-chain fatty acids (VLCFAs) are the main constituents of hydrophobic polymers that prevent dessication at the leaf surface and provide stability to pollen grains. Of the 21 genes encoding VLCFA elongases (VLCFAEs) from Arabidopsis thaliana, 17 were expressed heterologously in Saccharomyces cerevisiae. Six VLCFAEs, including three known elongases (FAE1, KCS1, and KCS2) and three previously uncharacterized gene products (encoded by At5g43760, At1g04220, and At1g25450) were found to be enzymatically active with endogenous yeast fatty acid substrates and to some extent with externally supplied unsaturated substrates. The spectrum of VLCFAs accumulated in expressing yeast strains was determined by gas chromatography/mass spectrometry. Marked specificity was found among elongases tested with respect to their elongation products, which encompassed saturated and monounsaturated fatty acids 20-30 carbon atoms in length. The active VLCFAEs revealed highly distinct patterns of differential sensitivity to oxyacetamides, chloroacetanilides, and other compounds tested, whereas yeast endogenous VLCFA production, which involves its unrelated elongase (ELO) in sphingolipid synthesis, was unaffected. Several compounds inhibited more than one VLCFAE, and some inhibited all six active enzymes. These findings pinpoint VLCFAEs as the target of the widely used K(3) class herbicides, which have been in commercial use for 50 years, provide important clues as to why spontaneous resistance to this class is rare, and point to complex patterns of substrate specificity and product spectrum among members of the Arabidopsis VLCFAE family.